Ab initio many-body effects in TiSe₂: A possible excitonic insulator scenario from GW band-shape renormalization
- Cazzaniga, M. Università degli Studi di Milano, Physics Department, Milano, Italy - European Theoretical Spectroscopy Facility (ETSF)
- Cercellier, H. Institut Néel, CNRS and UJF, Grenoble, France
- Holzmann, M. LPTMC, CNRS and UPMC, Paris and LPMMC, CNRS and UJF, Grenoble, France - European Theoretical Spectroscopy Facility (ETSF)
- Monney, Claude Synchrotron Radiation and Nanotechnology Department, Paul Scherrer Institut, Villigen, Switzerland
- Aebi, Philipp Département de Physique and Fribourg Center for Nanomaterials, Université de Fribourg, Switzerland
- Onida, Giovanni Università degli Studi di Milano, Physics Department, Milano, Italy - European Theoretical Spectroscopy Facility (ETSF)
- Olevano, V. Institut Néel, CNRS and UJF, Grenoble, France - European Theoretical Spectroscopy Facility (ETSF)
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08.05.2012
Published in:
- Physical Review B - Condensed matter and materials physics. - 2012, vol. 85, no. 19, p. 195111
English
We present both theoretical ab-initio results within the Hedin's GW approximation and experimental angle-resolved photoemission and scanning tunneling spectroscopy measurements on TiSe₂. With respect to the density-functional Kohn-Sham metallic picture, the many-body GW self-energy leads to a ≈0.2-eV band-gap insulator consistent with our STS spectra at 5 K. The highest valence and the lowest conduction bands are strongly renormalized, with a loss of k² parabolic dispersion toward a k⁴ shape. In particular, GW moves the top of valence moved toward a circle of points away from Γ, arising in a Mexican hat shape commonly associated with an excitonic insulator. Our calculations are in good agreement with experiment.
- Faculty
- Faculté des sciences et de médecine
- Department
- Département de Physique
- Language
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- English
- Classification
- Physics
- License
- License undefined
- Identifiers
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- RERO DOC 29645
- DOI 10.1103/PhysRevB.85.195111
- Persistent URL
- https://folia.unifr.ch/unifr/documents/302507
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